Speaking on the Senate floor, Kaine particularly denounced Pruitt's disregard for science when making environmental decisions while serving as Oklahoma attorney general, and his history of siding with "polluters" over public health.

"Virginians are pro-science people," Kaine said. "The political figure we most venerate is still Thomas Jefferson, who was the pre-eminent scientist of his day. Second, the evidence from Mr. Pruitt's career demonstrates he's anti-science in the climate area and possibly others. And, third, there is no position in the federal government that more relies upon accurate science and scientific judgment than EPA administrator."

Despite such fervent opposition, Pruitt advanced closer to confirmation after the chamber voted 54 to 46 in his favor, with two Democrats breaking ranks to support him. According to reports, a final vote could come by Friday evening. One Republican senator, Susan Collins of Maine, has said she believes he's unfit for the job and will vote against his nomination.

Virginia is the second-most vulnerable state to the effects of climate change, and coastal Hampton Roads is at particular risk.

"What we're seeing throughout Hampton Roads, Virginia, is that neighborhoods where you could sell or buy a house 15 years ago, you now can't because normal tidal action renders the home impossible to sell," Kaine told the chamber. "It affects businesses. The main road into the largest naval base in the world in Norfolk by 2040 will be covered two to three hours a day just by normal tidal action.

"Now, the cities of Norfolk, Virginia Beach, Portsmouth, Suffolk, Chesapeake, Newport News, Hampton — all are trying to figure out ways to make resiliency investments to protect against sea level rise."

The overwhelming consensus among climate scientists the world over is that greenhouse gases from burning fossil fuels is a chief driver of climate change. But just four months ago, Kaine said, Pruitt was still making statements skeptical of such climate science.

Pruitt was also one of a number of attorneys general who filed an amicus brief in an unsuccessful bid by farm groups to challenge EPA's authority to impose a pollution diet on Virginia and other states in the bay watershed. States worked with EPA in 2010 to draw up their own plans to meet their pollution limits. Now studies show those measures are working and the bay is getting healthier.

"I worry that, if Mr. Pruitt denies science on this matter," Kaine said, "what other science will he deny?"

Reaction to Pruitt's nomination falls largely along party lines. Republican Sen. Shelley Moore Capito of West Virginia called Pruitt the most thoroughly vetted candidate ever named to head the EPA.

She praised his commitment to rein in what many consider EPA's overreach and to reform the rule-making process "to prevent another open assault on our economy by unelected bureaucrats."

"I've watched him in action in terms of questioning the overreach in the court systems," Capito told the chamber. "I have confidence that he embodies the leadership that we need to restore the confidence and accountability of the EPA to benefit the public health, to benefit environmental preservation and to also look at that much-needed economic growth that needs to be the balance that we want to see restored back to the EPA."

Kaine also noted that an EPA administrator must strike the right balance. But he had no confidence that Pruitt is the right man for the job.

In one example, Kaine said, Pruitt as attorney general submitted comments on behalf of his state expressing skepticism that fracking could harm water quality or cause seismic instability.

"Was the comment backed by science?" Kaine asked. "Was it backed by a deep analysis that had been done by scientists or smart attorneys in Mr. Pruitt's office? No. In this instance (the comment) was actually written by an energy company, copied and pasted onto official Oklahoma letterhead and submitted to the EPA as representing the view of Oklahoma public officials.

"In virtually every decision," Kaine added, "the attorney general's office defended the interests of oil and gas, of big agribusiness and, basically, the interests of polluters against the interests of clean air and water, which are the interests of our families and our kids."